Olympus doesn't stand by the OMD EM5's ability to keep out water or sand

I sent off the camera to Olympus, and after having to chase them for information on the progress, I was told I had misused the camera.

"Olympus Customer Support Centre has advised that the fault has been caused by misuse (sand ingress/liquid ingress/impact damage...) Please, see attached pictures. [low res]

As you will appreciate, the Olympus warranty is not ‘unconditional’, and therefore faults caused by misuse cannot be covered under the defect in manufacture warranty.  I therefore enclose a quotation for the cost of the repair"

"The BARRIER requires attention - £397.32"

Three low res images that I don't see related to the shutter malfunction, a very short explanation and a demand for £397.32.

Have I misused this camera? I would appreciate your comments.